Even with the advancement of telecommunication networks towards long term evolution (LTE) and other such advanced technologies, there is still a requirement for maintaining call continuity across various networks. Further, the term “network convergence” is becoming very popular in the advanced telecommunication networks. Furthermore, the concept of “voice call continuity” (VCC) is starting to emerge from a cell-to-cell movement towards a network-to-network movement. The VCC requires maintaining a voice call during the network-to-network movement when the telecommunication networks are based on various technologies. For example, the VCC requires seamlessly maintaining a voice call when a user/subscriber moves from one telecommunication network that is based on one technology, for example, a second generation (2G) network or a WiMax based network to another telecommunication network that is based on another technology, for example, a third generation (3G) network or a Wi-Fi based network.
Based on existing technologies, in the above-described scenario, if a user/subscriber moves from one network to another network and the user is lawfully intercepted by a law enforcement agency (LEA), such a lawfully intercepted call cannot be re-established and maintained in the network-to-network movement during the entire period without the user knowing it. This is because the infrastructure needed for doing lawful interception of a call is not unified and varies based on different technologies and the real-time communication may go from circuit switching to packet based switching. Further, the telecommunication networks based on different technologies operate under different frequency ranges. Furthermore, the interface protocols needed between telecommunication networks based on different technologies and mobile stations operate under different standards. Typically in such a scenario, the call may either get dropped or the LEA may be unable to continue the lawful interception of the call. In both the scenarios, the LEA can lose the needed important data/voice associated with the conversation of the lawfully intercepted user/subscriber.